Device for rotary latching and unlatching

ABSTRACT

A device for automatically releasing a rotary knob which has a latched position. In a record changer a slide is provided on a switching drum which is supported by a knob spindle. A slide end together with a drum surface constitute a curved track with latching cavities. The slide is withdrawn into the drum by spindle rotation relative to the drum for unlatching.

United States Patent Eisemann 51 Sept. 30, 1975 DEVICE FOR ROTARY LATCHING AND UNLATCHING Inventor: Kurt Eisemann, Berlin, Germany U.S. Philips Corporation, New York, NY.

Filed: Sept. 28, 1973 Appl. No.: 401,720

Assignee:

Foreign Application Priority Data Oct. 13, 1972 Germany 2250l79 US. Cl. 74/527; 74/25; 292/l69.2l Int. Cl. G05G 5/06 Field of Search 74/25, 527, 22, 23, 27,

References Cited UNITED STATES PATENTS Campbell 292/169.21

Primary Eraminer-Samuel Scott Assistant Eraminer-Frank H. McKenzie, Jr. Attorney, Agent, or Firm-Frank R. Trifari; David R. Treacy [57] ABSTRACT A device for automatically releasing a rotary knob which has a latched position. In a record changer a slide is provided on a switching drum which is supported by a knob spindle. A slide end together with a drum surface constitute a curved track with latching cavities. The slide is withdrawn into the drum by spindle rotation relative to the drum for unlatching.

6 Claims, 5 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of2 3,908,481

p 0,1975 Sheet 2 of 2 3,8 81

' US. Patent DEVICE FOR ROTARY LATCHING AND UNLATCI-IING The invention relates to a device for automatically releasing a switching member from a latched position, in particular for automatically releasing a rotary knob used in a record changer or player, which knob has a latched position for pre-selection of the speed.

In record players or record changers which are actuated by means of a rotary knob, the knob generally assumes one or two latched positions. Such latched positions may serve to retain a starting position, a speedselection position etc. In record changers such knobs are then usually released by the changing mechanism when the apparatus is set to the stop position.

Automatic record players generally also incorporate an off-button.

An object of the invention is to provide a device in which automatic releasing is effected by merely turning back the knob.

In a device according to the invention a slide is disposed on a switching drum which is supported by a spindle. An end of the slide together with a drum surface from which the slide can be made to extend a certain distance, form a curved track with latching cavities the slide is withdrawn into the drum when the spindle is rotated relative to the drum, the latching cavities being eliminated.

When the knob is set to one of the latched positions, a control member, for example, a pin, can engage the latching cavity. The knob and the drum respectively then cannot return to the initial position, because this is prevented by the pin engaging the latching cavity. The drum can return only when the slide is withdrawn, thus allowing the pin to advance.

According to an embodiment of the invention the slide can be withdrawn into the drum by means on a cam of the spindle which acts on the slide against the action of a spring. The spring which biases the slide ensures that the knob cannot be readily rotated with respect to the drum, so that the knob must be turned towards the zero position with increased force. When this happens, the slide recedes and releases the pin.

In a particular embodiment of the invention the slide is radially movable relative to the drum, the pins which are radially mounted on a diameter of the drum engaging longitudinal slots of the slide. This contruction provides a rotary coupling between the slide and the drum; moreover, it provides a radial guidance for the slide.

According to further embodiment of the invention the longitudinal slot, which the pin located at the side of the curved track engages has surfaces which diverge towards the outside of the drum and which extend parallel to the stop surfaces against which the control member butts under the influence of a return force. This ensures that the slide moves slightly away from the pin as it recedes against the spring force, which facilitates the withdrawal and sliding operation.

In a suitable embodiment of the invention the return force is exerted by a stop roller, which in the latched.

position of the drum presses against a flank of a latching cavity. As a result, the pin of the control member which has engaged with the latching cavity will always exert a certain pressure on the stop surface.

It is obvious that the drum may also be a disc, if the drum is not intended for other switching purposes.

The invention will now be explained in more detail with reference to the embodiment shown in the drawing.

FIG. 1 is an axial bottom plan view of a drum and a slide according to the invention, the drum being in the off-position,

FIG. 2 is a plan view of the device according to FIG. 1 in a latched position,

FIG. 3 is a plan view of the device when rotated beyond its operating position,

FIG. 4 is a plan view of the device with withdrawn slide, and

FIG. 5 is a a sectional view of the complete device with control knob.

A drum 3 is pivoted in a mounting plate 1 which is shown in FIG. 5. A control spindle 5 extends through the drum 3, fitted so as to be pivotable with respect to the drum. The spindle can be rotated by means of a knob 9 at the upper surface 7 of the mounting plate. Two pins 11 which extend downwards from the drum 3 are located at the same diameter. The pins 1 1 provide the radial guidance of a slide 13 in the longitudinal direction. Two compression springs 15, which bear on a surface 17 of the drum 3, press the slide 13 to the left in FIG. 5, in such a way that the front surface 19 of the slide (see FIG. 4) together with the surface 21 of the drum form a curved track for a stop pin 23, which is attached to a control lever 25. The control lever 25 is pivoted in a pivot 27 and the spring 29 tends to move the lever in such a Way that the stop pin 23 always engages the surfaces 19 and 21 respectively.

In addition to the pins 1 l, which extend through axial slots 31 and 31 respectively of the slide 13, the spindle 5 extends through a slot 33 of the slide 13. Laterally projecting cams 35 provided on the spindle abut a stop surface 37 of the slide.

In the zero or off-position according to FIG. 1, a stop roller 41 engages a latching cavity 39 of the drum 3, said roller being pivoted to a slide 43. The slide 43, in turn, can only be moved axially in the direction of the arrows 45 and a compression spring 47 ensures that the slide 43 always presses the stop roller 41 against the drum 3.

If the knob 9 is subsequently turned from the zero position in the direction of an arrow 49 (FIG. 2), the pin 23 moves over the front surface 19 of the slide 13 and engages a latching cavity 51, from which the pin can not become disengaged by itself. During this the stop roller 41 has rolled out of the zero cavity 39. The spindle 53, however, is still radially in the region of the latching cavity 39, so that the stop roller 41 exerts a return pressure on the flank 55 of the latching cavity. However, returning is not possible, because the pin 23 engages the stop surface 57 of the latching cavity 51.

By means of the switching device a further movement can be performed, which is shown in FIG. 3. When the drum 3 is turned still further in the direction of the arrow 49 by means of the knob 9, the pin 23 advances to an end position against the stop surface 61, in which position a switching function can be performed which is not further described. With the aid of a spring, not shown, this drum returns to the position of FIG. 2 upon release of the knob.

If the complete device is to be reset to the zero and initial position of FIG. 1, one of the earns 35 is pressed against the corresponding stop surface 37. As a result, the slide 13 is moved against the action of the spring 15, and the front surface 19 of the slide is withdrawn into the drum, so that the latching cavities disappear and the parts 21 and 19 of the curved track form one continuous surface. Thus, the pin 23 is allowed to return to the zero position over the surface 19. The movement of the pin to the zero position and the withdrawal of the slide 13 is facilitated in that the stop surfaces 57 of the latching cavities 51 and the wall surfaces 63 of the recess 31 extend outwards in substantially parallel pairs. Consequently, the slide 13 can slightly recede and thus facilitate the passage of the stop pin 23.

The movement cycles are always the same, irrespective of whether the drum was first turned in the direction of arrow 49 or arrow 49. In any case it is necessary for the return to the zero position that greater pressure is exerted on the knob 9, to ensure that the slide can recede against the action of the springs.

What is claimed is:

l. A device for rotating a switching member and for automatically releasing the member from a latched position, comprising a switching member mounted for rotation about an axis and having a first curved track surface, means for mounting a spindle for rotation about said axis, means for actuating said spindle, latching means connected to said switching member, having a second curved track surface for movement from a normal position in which said second curved track surface and said first curved track surface constitute a discontinuous track having latching cavities to an unlocked position in which said first and second surfaces form a continuous curved track surface, said device further comprising means for biasing said latching means from said unlocked toward said normal position, and means coupling said spindle to said latching means for rotating said switching member in response to rotation of said spindle when said member is free to rotate and for transmitting force to overcome said biasing means and moving said latching means from said normal to said unlocked position when latching engagement of said switching member by a control member prevents rotation of said switching member.

2. A device as claimed in claim 1, wherein said latching means comprises an elongated slide mounted on said switching member for slidable movement between normal and unlocked positions perpendicular to said axis, said second track surface being formed on an end of said slide projecting beyond said first track surface in the normal position of said slide, a side portion of said projecting end having a latching surface diverging outward toward said end for latching engagement by a control member, said projecting end being withdrawn into said switching member when said slide is in said unlocked position.

3. A device as claimed in claim 2, wherein said slide has a longitudinal slot therethrough adjacent said end, said slide having a wall surface of said slot diverging from the longitudinal axis of said slide toward said end, and wherein said switching member comprises a pin adjacent said first track surface extending parallel to said axis through said slot of the slide.

4. A device as claimed in claim 3, wherein said wall surface is parallel to said latching surface.

5. A device as claimed in claim 2, wherein said rotating and force transmitting means comprises first and second laterally projecting cams on opposite sides of the spindle and corresponding first and second stop surfaces on the slide so arranged that, from a first position of the switch member in which a control member abuts the second track surface, rotation of the spindle in a first direction causes the first cam surface to bear against the first stop surface and to rotate the switching member, and from a second position of the switching member in which a control member abuts the first track surface and a latching surface of the slide, rotation of the spindle in the opposite direction causes the second cam surface to bear against the second stop surface so as to move said slide from the normal to the unlocked position so that the switching member will then be free to rotate toward the first position.

6. A device as claimed in claim 5, wherein said switching member has a zero latching cavity, said device additionally comprising a stop roller biased to engage said cavity so arranged that in a latched position of the switching member the roller engages a flank of 

1. A device for rotating a switching member and for automatically releasing the member from a latched position, comprising a switching member mounted for rotation about an axis and having a first curved track surface, means for mounting a spindle for rotation about said axis, means for actuating said spindle, latching means connected to said switching member, having a second curved track surface for movement from a normal position in which said second curved track surface and said first curved track surface constitute a discontinuous track having latching cavities to an unlocked position in which said first and second surfaces form a continuous curved track surface, said device further comprising means for biasing said latching means from said unlocked toward said normal position, and means coupling said spindle to said latching means for rotating said switching member in response to rotation of said spindle when said member is free to rotate and for transmitting force to overcome said biasing means and moving said latching means from said normal to said unlocked position when latching engagement of said switching member by a control member prevents rotation of said switching member.
 2. A device as claimed in claim 1, wherein said latching means comprises an elongated slide mounted on said switching member for slidable movement between normal and unlocked positions perpendicular to said axis, said second track surface being formed on an end of said slide projecting beyond said first track surface in the normal position of said slide, a side portion of said projecting end having a latching surface diverging outward toward said end for latching engagement by a control member, said projecting end being withdrawn into said switching member when said slide is in said unlocked position.
 3. A device as claimed in claim 2, wherein said slide has a longitudinal slot therethrough adjacent said end, said slide having a wall surface of said slot diverging from the longitudinal axis of said slide toward said end, and wherein said switching member comprises a pin adjacent said first track surface extending parallel to said axis through said slot of the slide.
 4. A device as claimed in claim 3, wherein said wall surface is parallel to said latching surface.
 5. A device as claimed in claim 2, wherein said rotating and force transmitting means comprises first and second laterally projecting cams on opposite sides of the spindle and corresponding first and second stop surfaces on the slide so arranged that, from a first position of the switch member in which a control member abuts the second track surface, rotation of the spindle in a first direction causes the first cam surface to bear against the first stop surface and to rotate the switching member, and from a second position of the switching member in which a control member abuts the first track surface and a latching surface of the slide, rotation of the spindle in the opposite direction causes the second cam surface to bear against the second stop surface so as to move said slide from the normal to the unlocked position so that the switching member will then be free to rotate toward the first position.
 6. A device as claimed in claim 5, wherein said switching member has a zero latching cavity, said device additionally comprising a stop roller biased to engage said cavity so arranged that in a latched position of the switching member the roller engages a flank of the cavity. 